Measurement of abdominal aortic aneurysms with three-dimensional ultrasound imaging: Preliminary report

Objective: Accurate measurements of abdominal aortic aneurysms (AAAs) are r equired for surgical planning and monitoring over time. We have examined th e feasibility of using a three-dimensional (3-D) ultrasound imaging system to derive quantitative measurements of interest from AAAs. Methods: A normal aorta, a small AAA, and an AAA repaired with an endovascu lar stent graft were scanned with a 3-D ultrasound imaging system. For each case, a 3-D surface reconstruction was generated from manual outlines of a sequence of two-dimensional ultrasound images, registered in 3-D space wit h a magnetic tracking system. The surfaces were resampled in planes perpend icular to the vessel center axis to calculate cross-sectional area and maxi mum diameter as a function of distance along the length of the aorta. Results: Cross-sectional area and maximum diameter were plotted along the l ength of the aneurysmal aortas from the renal arteries to the aortic bifurc ation. The overall maximum diameter was found for both aneurysms. For the s mall AAA, the distances of the aneurysm from the renal arteries and the bif urcation were measured. For the repaired AAA, the location of the stent gra ft relative to the renal arteries was measured. Conclusions: 3-D surface reconstructions from ultrasound images show promis e for quantitatively characterizing the geometry of AAAs both before surger y and after endovascular repair.